[REG 5.9.9 -> 5.15.2] Qt Example Simple Browser Memory Increase : Website with download file periodically

I use the 'simplebrowser' example to visit a local website which provide periodically image.

The request are url like this : 

http://192.168.2.140/LIVE_SNAPSHOT/SNAP_INPUT_6.png?time=1611573979410
http://192.168.2.140/LIVE_SNAPSHOT/SNAP_INPUT_7.png?time=1611573979910
http://192.168.2.140/LIVE_SNAPSHOT/SNAP_INPUT_8.png?time=1611573980410
http://192.168.2.140/LIVE_SNAPSHOT/SNAP_INPUT_6.png?time=1611573980910

The content is fetch each 500ms and overwritten by new.
When I use the simplebrowser for 3-4h hours the memory increase to 1GO and continue on Windows and MacOS but in Linux (ubuntu 18.04) the memory doesn't grow.